ruby, 72 bytes

Result

AC

Duration

2458ms

Code [DL]

s=`dd`;puts s.gsub(/^(.{#{s=~/T/}}) /,'\1#').sub(/K */){?K+?#*~-$&.size}

stdin

                                T                 
                                                  
    K                                             

stdout

                                T                 
                                #                 
    K############################                 

stderr

0+1 records in
0+1 records out

strace